PROBLEM TO BE SOLVED : To provide a photostimulable phosphor which is free from performance degradation by moisture absorption, can be used for a long time while exhibiting good performance, and provides a radiation-image conversion panel excellent in image characteristics; its preparation method; and a radiation-image conversion panel.
SOLUTION : The photostimulable phosphor is represented by formula (1) : (Ba1-xM1)FBryI1-yX : aM2, bLn, cO, and its preparation method is characterized by that, after firing, phosphor particles in a photostimulable phosphor is subjected to surface treatment with a fluorine-containing compound. In formula (1), M1 is at least one alkaline earth metal atom selected from among Mg, Ca, Sr, Zn, and Cd; M2 is at least one alkali metal atom selected from among Li, Na, K, Rb, and Cs; X is at least one halogen atom selected from among Cl, Br, and I; Ln is at least one rare earth atom selected from among Ce, Pr, Sm, Eu, Gd, Tb, Tm, Dy, Ho, Nd, Er, and Yb; 0≤x≤0.3; 0≤y≤0.3; 0≤a≤0.05; 0
